Abstracts

Rationale: An important component of pre-surgical decision making for patients with pharmacoresistent temporal lobe epilepsy is the neuropsychological study. Vale et al. has a transsylvian approach selective mesial temporal lobe resection procedure exhibiting excellent seizure freedom rates. However, limited data are available on neuropsychological outcome from this surgical approach. Further, there are limited data on the ecological validity of the Wechsler Memory Scale-4th Ed. (WMS-IV) to predict outcome of temporal lobectomy. This study evaluated the ability of the WMS-IV to predict outcome from left and right TLE in a sample of patients with pharmacoresistent TLE. The predictive accuracy of the WMS-IV will be compared to a measure with established clinical validity to predict post-surgical outcome, the Rey Auditory Verbal Learning Test (RAVLT). Methods: Prospective study of patient s referred to Florida regional epilepsy program. All patients included in the study had TLE and consented to voluntary neurosurgery for temporal lobectomy. Patients also must have underwent pre surgical and post-surgical neuropsychological evaluations. Participants: A total of 19 participants met criteria for inclusion in this study. There were 9 left TLE (LTLE) and 10 right TLE(RTLE) patients. Variables/Measures: All participants completed comprehensive neuropsychological evaluations which included the WMS-IV, RAVLT and ROCFT and intracarotid methohexital (Wada) testing.Results: There were no significant differences between the LTLE and RTLE groups in demographic variables, disease variables (duration of seizures) or IQ. At pre-surgery, ANOVA did not identify significant differences between LTLE and RTLE groups in the WMS-IV primary memory indices (Auditory, Visual, Immediate, or Delayed memory). Post-operatively, evaluation found patients having left ATL scored significantly worse than patients with RTLE on the RAVLT short (p<.05) and long-delay (p<.05) memory trials and the WMS-IV Logical Memory-I (LM-I) and LM-II long delay trials (p<.05). Trends were found for predicting Right ATL outcome. RAVLT better predicted outcome of left ATL than WMS-IV indices.Conclusions: These data raises questions about the added clinical utility of the WMS-IV beyond the clinical utility provided by the RAVLT in predicting outcome from left (language dominant) selective temporal resections. The WMS-IV visual memory tasks were weak predictors of post-operative outcome from selective right ATL. This study is limited by small sample size and larger samples is needed.